Featured Research

from universities, journals, and other organizations

To Peer Inside A Living Cell: Quantum Mechanics Could Help Build Ultra-high-resolution Electron Microscopes

Date:
October 7, 2009
Source:
Massachusetts Institute of Technology
Summary:
Electrical engineers have proposed a new scheme that can overcome a critical limitation of high-resolution electron microscopes: they cannot be used to image living cells because the electrons destroy the samples. The researchers suggest using a quantum mechanical measurement technique that allows electrons to sense objects remotely without ever hitting the imaged objects, thus avoiding damage.

An electron microscope image of a butterfly's wings.
Credit: Graphic: Christine Daniloff; electron micrograph image courtesy of the NSF

Electron microscopes are the most powerful type of microscope, capable of distinguishing even individual atoms. However, these microscopes cannot be used to image living cells because the electrons destroy the samples.

Now, MIT assistant professor Mehmet Fatih Yanik and his student, William Putnam, propose a new scheme that can overcome this limitation by using a quantum mechanical measurement technique that allows electrons to sense objects remotely. Damage would be avoided because the electrons would never actually hit the imaged objects.

Such a non-invasive electron microscope could shed light on fundamental questions about life and matter, allowing researchers to observe molecules inside a living cell without disturbing them. Yanik and Putnam report their new approach in the October issue of Physical Review A — Rapid Communications.

If successful, such microscopes would surmount what Nobel laureate Dennis Gabor concluded in 1956 was the fundamental limitation of electron microscopy: "the destruction of the object by the exploring agent."

Electron flow

Electron microscopes use a particle beam of electrons, instead of light, to image specimens. Resolution of electron microscope images ranges from 0.2 to 10 nanometers — 10 to 1,000 times greater than a traditional light microscope. Electron microscopes can also magnify samples up to two million times, while light microscopes are limited to 2,000 times.

However, biologists have been unable to unleash the high power of electron microscopes on living specimens, because of the destructive power of the electrons.

The radiation dose received by a specimen during electron microscope imaging is comparable to the irradiation from a 10-megaton hydrogen bomb exploded about 30 meters away. When exposed to such energetic electron beams, biological specimens experience rapid breakdown, modification of chemical bonds, or other structural damages.

Although there exist special chambers to keep biological samples in a watery environment within the high vacuum required for electron microscopes, chemical preservation or freezing, which kill cells, is still required before biological samples can be viewed with existing electron microscopes.

In the proposed quantum mechanical setup, electrons would not directly strike the object being imaged. Instead, an electron would flow around one of two rings, arranged one above the other. The rings would be close enough together that the electron could hop easily between them. However, if an object (such as a cell) were placed between the rings, it would prevent the electron from hopping, and the electron would be trapped in one ring.

This setup would scan one "pixel" of the specimen at a time, putting them all together to create the full image. Whenever the electron is trapped, the system would know that there is a dark pixel in that spot.

Though technical challenges would need to be overcome (such as preventing the imaging electron from interacting with electrons of the metals in the microscope), Yanik believes that eventually such a microscope could achieve a few nanometers of resolution. That level of resolution would allow scientists to view molecules such as enzymes in action inside living cells, and even single nucleic acids — the building blocks of DNA.

Yanik, the Robert J. Shillman Career Development Assistant Professor of Electrical Engineering, says he expects the work will launch experimental efforts that could lead to a prototype within the next five years.

Charles Lieber, professor of chemistry at Harvard and an expert in nanoscale technology, describes Yanik's proposal as a "highly original and exciting concept for 'noninvasive' high-resolution imaging" using an electron microscope.

"From my perspective, it has the potential to be a breakthrough for those working with sensitive samples, such as biological imaging," Lieber says. "Also, in general terms I find his work intellectually exciting because it is not incremental but takes a quantum (excuse the pun) jump forward through creative thinking."


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Anne Trafton, MIT News Office. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute of Technology. "To Peer Inside A Living Cell: Quantum Mechanics Could Help Build Ultra-high-resolution Electron Microscopes." ScienceDaily. ScienceDaily, 7 October 2009. <www.sciencedaily.com/releases/2009/10/091006134825.htm>.
Massachusetts Institute of Technology. (2009, October 7). To Peer Inside A Living Cell: Quantum Mechanics Could Help Build Ultra-high-resolution Electron Microscopes. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2009/10/091006134825.htm
Massachusetts Institute of Technology. "To Peer Inside A Living Cell: Quantum Mechanics Could Help Build Ultra-high-resolution Electron Microscopes." ScienceDaily. www.sciencedaily.com/releases/2009/10/091006134825.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japan Looks To Faster Future As Bullet Train Turns 50

Japan Looks To Faster Future As Bullet Train Turns 50

Newsy (Oct. 1, 2014) Japan's bullet train turns 50 Wednesday. Here's a look at how it's changed over half a century — and the changes it's inspired globally. Video provided by Newsy
Powered by NewsLook.com
US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins